The subject matter discussed in the background section should not be assumed to be prior art merely as a result of its mention in the background section. Similarly, a problem mentioned in the background section or associated with the subject matter of the background section should not be assumed to have been previously recognized. The subject matter in the background section merely represents different approaches.
In conventional database systems, users access their data resources in one logical database. A user of such a conventional system typically retrieves data from and stores data on the system using the user's own systems. A user system might remotely access one of a plurality of server systems that might in turn access the database system. Data retrieval from the system might include the issuance of a query from the user system to the database system. The database system might process the request for information received in the query and send to the user system information relevant to the request.
As an on demand platform, Apex™ provides a set of features for building business applications including, for example, data models and objects to manage data, a workflow engine for managing collaboration of that data, a user interface model to handle forms and other interactions, and a Web services application programming interface (API) for programmatic access and integration. These platform technologies support custom applications and integrations, and allow developers to build applications utilizing this on demand model.
Apex code is “on demand,” running without requiring local servers or software. Apex code may run in a multi-tenant environment, providing the economic and manageability benefits of a shared service while keeping the definition, data and behavior of each customer's application separate from each other. For developers, the combination of these capabilities with this on-demand, multi-tenant delivery provides convenience, scalability, and safety of an on-demand database, combined with the flexibility and control of a procedural language.
Apex code provides a powerful and productive approach to creating functionality and logic, allowing developers to focus on elements specific to their application, while leaving other elements to the platform's framework. Apex code is a successful and innovative language in part because of its multi-tenant design. Multi-tenancy allows Apex to scale to a large number of customers with a relatively modest hardware investment. Apex code is abstracted and governed, utilizing only as many resources as is allowed.
Performance is a key requirement for any programming language. It is especially important in a multi-tenant environment where processor cycles spent interpreting code for a given customer have a direct and negative impact on other customers sharing the same environment. Thus, improving performance not only results in quicker response times for users but also less impact on other tenants in terms of the overall load on the system.
All languages tend to have some start-up cost associated with getting code into a state where it can be executed. This cost includes, for example, the processing required to load the executable form of the code and to link it with dependent code. Unlike most programming languages, however, start-up costs tend to dominate in a multi-tenant language where the interpreter may be called upon to execute code from any one of possibly thousands of tenants. The ability to cache executable code to avoid the start-up costs on subsequent requests is limited by the large working set. In addition, the requests tend to be relatively short, making the start-up cost a larger proportion of the overall request time.